RAID 10 with four 2 TB drives: mirrored stripes for speed and safety
RAID 10 with four 2 TB drives combines mirroring and striping: data is striped across two mirrored pairs, giving you 4 TB of usable capacity from 8 TB raw (50% overhead). Read and write speeds are roughly double a single drive, and the array can survive at least one drive failure, potentially two if the failed drives are in different mirror pairs.
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Storage Efficiency
Survives 1 drive failure
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RAID 10 is the performance king among redundant RAID levels. Unlike RAID 5/6, there's no parity calculation penalty on writes, which makes random write performance dramatically better. This makes it the preferred choice for database servers, virtualization hosts, and any workload with heavy random I/O. The 50% capacity overhead is steep, but for performance-sensitive applications where downtime is expensive, it's the standard. Rebuild times are also much faster than RAID 5/6 because there's no parity to recalculate; the controller just copies data from the surviving mirror to the replacement drive.
Verdict
RAID 10 is the right choice when performance and uptime both matter and you're willing to pay the 50% capacity premium. For a home NAS serving mostly media files, the capacity overhead makes it hard to justify over RAID 5 or 6. But for a VM host or database server, RAID 10 pays for itself in IOPs.
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Frequently asked questions
Can RAID 10 survive two drive failures?
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